This chapter discusses epidemiologic studies of nonsmokers exposed to tobacco product smoke that have evaluated lung function or respiratory symptoms, most of which have evaluated children. The effects of active cigarette smoking are briefly reviewed to recount the reasons why certain aspects of lung function have been studied in nonsmokers. The plausibility of finding similar effects in nonsmokers exposed to ETS is discussed and the studies found in the literature are assessed.
Cross-sectional studies of smokers have demonstrated that smokers, compared with nonsmokers, have (1) an increased prevalence of chronic cough, chronic sputum production, and wheezing and (2) decreased lung function (see U.S. Public Health Service, 1984, for an extensive review). The effects of smoking on both respiratory symptoms and lung function may be seen within a few years of the onset of regular smoking (U.S. Public Health Service, 1979, 1984; Woolcock et al., 1984). Longitudinal studies have demonstrated that the mean rate of decline with age of the 1-second forced expiratory volume (FEV1) is greater in smokers than in nonsmokers. In some smokers, the rate of decline of FEV1 is rapid, leading to clinically important chronic airflow obstruction.
The structural changes associated with active cigarette smoking are seen in both the conducting airways and the pulmonary parenchyma (for a more detailed description, see U.S. Public